1. Field of the Invention
The present invention relates to a running control apparatus for a vehicle which can run in a low fuel-consumption mode, in particular, a running control apparatus for further improving the fuel consumption.
Priority is claimed on Japanese Patent Application No. 2006-126713, filed Apr. 28, 2006, the content of which is incorporated herein by reference.
2. Description of the Related Art
In a known example of a hybrid vehicle, the vehicle speed is controlled when the accelerator is not operated (i.e., OFF), and when acceleration is required during the vehicle speed control, a torque assisting operation is performed using a motor, so as to control the deceleration and improve the fuel consumption (see Japanese Unexamined Patent Application, First Publication No. 2005-160252).
In the above known example, the deceleration control is performed only when the accelerator is OFF, so as to control the quantity of assistance (i.e., assisted torque) based on an amount of remaining power of a battery, an inter-vehicle distance between the present vehicle and a vehicle ahead thereof, a relative velocity, and various data with respect to the running state of the vehicle. However, actually, the quantity of assisted torque is uniformly set using values defined in a map or a table, which may not be satisfactory to the driver. Therefore, when the driver feels a large deceleration while the accelerator is OFF, the driver may depresses the accelerator pedal again. If such a depression of the accelerator pedal is repeated, the fuel consumption cannot be improved.